66 PROCEEDINGS OF THE ACADEMY OP [18T9. 



ON THE VARIABILITY OF SPH.ERIA QUERCUTJM, Schw. 

 BY J. B. ELLIS. 



Among the Sphreriaceous fungi of Southern New Jersey, no 

 species perhaps is oftener met with than Spheeria Quercuum, 

 Schw. And perhaps, it might be added, no species is more diffi- 

 cult to define and classify. Fries includes it among the " Conflu- 

 entes," remarking (Elench. ii. p. 84) that many species of that 

 section approach very near to the Dothideas. Berkeley, in " Gre- 

 villea," places it in Melogramma, taking that genus doubtless as 

 defined in his Outlines of British Fungology, p. 391, and by Fries 

 in Sum. Yeg. Scan. p. 386. Tulasne, however, who had exam- 

 ined this species, did not include it his genus Melogramma (see 

 his Selecta Fungorum Carpologia, vol. ii. p. 81). 



On examining the two genera, Melogramma and Dothidea, it 

 will be seen that there are no salient and unmistakable characters 

 by which they maj- be distinguished. Tulasne, 1. c, says of his 

 genus Melogramma, " Perithecia globosa ex parietibus nunc e 

 parenchymate materno vix distinctis nee solubilibus, nunc contra 

 sine negotio sejungendis facta ;" a definition which will include 

 two different types of perithecia, viz., those with walls not sepa- 

 rable from the substance of the stroma, and others with walls 

 readily separable ; in the former case scarcely distinguishable 

 from Dothidea, in which genus the ascigerous nucleus is contained 

 in cavities in the stroma without any distinct perithecium. Per- 

 haps the most obvious character separating the two genera may 

 be found in the stroma which is more highly developed in 

 Dothidea; but even here species occur, Dothidea perisporioides^ 

 B. & C. for example, where the stroma is so imperfectly developed 

 as to leave the classification somewhat doubtful. Not less difficult 

 is it to refer to their proper place the various forms of Sphseria 

 Quercnum, Schw., occurring as it does now scattered and distinct, 

 and again, on the same branch, confluent and united in a stroma 

 more or less evident ; now with hardly a trace of an ostiolum, and 

 again with a distinct cjdindric beak equalling in length one-fourth 

 or one-third the height of the perithecium itself. The various 

 forms, however, all agree in having normally a subcuticular origin, 

 on the surface of the inner bark, just beneath the epidermis, which 



